Full details of these measurements have been published previously [2]. Statistical analyses were performed using linear model software in DataDesk 6.1.1 (Data Description Inc, Ithaca, NY). Differences between NPNL and lactating women, at the time of their first measurement, were investigated using Student’s two-tailed t-test. Descriptive statistics are reported as means and standard deviations. Changes over time are reported as means and standard 3-MA datasheet errors.

Scheffe’s post hoc method was used to reduce effects of multiple testing. All variables, except age, were transformed into natural logarithms to normalize skewness where necessary and to determine proportional (percentage) changes of discrete variables [30]. Independent determinants of changes PR-171 nmr in HSA variables were explored using multiple regression models. Determinants investigated included mean and changes in weight, and mean and changes in calcium intake using the FFQ data obtained at the different timepoints. In addition, data from individual

food diaries, obtained at a single timepoint were used to group women with calcium intakes above and below the median to investigate group differences using conditional regression analysis. The characteristics of the 48 lactating women at 2 weeks postpartum and 23 NPNL women at baseline are shown in Table 1. There were no significant differences in weight and height between the two groups but the NPNL Resminostat women were, on average, younger. BMDa was significantly lower for lactating women at the narrow neck (4.2%) and intertrochanter (5.3%) and these differences remained significant after adjusting for age. There were no significant differences for other hip measurements. There was a wide range in calcium intakes for both NPNL and lactating women but the NPNL women had significantly lower intakes of calcium at baseline

compared to the lactating women at 2 months postpartum (prospective food diary data expressed as mean [SD, range]: NPNL women 904 [196, 456–1160] mg/day; lactating women 1254 [416, 637–2280] mg/day). During the study, lactating women lost significant weight (2 weeks postpartum to peak-lactation −2.79 ± 0.72%, P < 0.001; 2 weeks postpartum to post-lactation −5.00 ± 0.83%, P < 0.0001). In contrast, NPNL women had no significant decrease in weight (0.51 ± 0.89%). The percentage changes in HSA measurements for lactating women from 2 weeks postpartum to peak-lactation and 2 weeks postpartum to post-lactation, are shown in Table 2. This table also reports the HSA changes observed for the NPNL women during the study. At peak-lactation, significant decreases in BMDa were observed at all three hip sites. Significant decreases in CSA were also observed at the narrow neck and intertrochanteric region. There were no significant changes in bone width at any site. Section modulus decreased significantly only at intertrochanter.